[Sinbad]

Originally Posted by fly*

@Sinbad

http://www.communica.co.za/ProductDe...P_001917995336

Shot!

I see it has a 250V relay... can it switch some 12V fans? (I have 2 12V pc fans in the cupboard)

[Baradhel]

Titanium works well. It's totally safe in salt water. You can't solder it though, since it oxidises instantly in contact with air.

[hotdog83]

You can get the ready made Auto Top Up units from the LFS, I think the ones I saw are Reeftek. They have a float switch and a small pump. The gravity ones are also cool, but then you will have to put the RO tank above the tank level, which might not look too good. With the Automated Auto Top Up units, they will have to be below the tank water level, so as to avoid a syphon back into the tank.

[fly*]

Shot!

I see it has a 250V relay... can it switch some 12V fans? (I have 2 12V pc fans in the cupboard)

Sinbad i'm not too sure tbh, i'll test it out tonight. I asked one of the guys there before I bought it and he said this would be exactly what I was looking at (and I mentioned PC fans). Either way it doesnt really matter. I would prefer to run 12V's through the circuit but if I have to run 240V's, you can do that as well, just run the 240V power positives through the relay that need to power the PC Fans transformer. Probably more effcient doing this as well.

[mariusmeyer]

How can one make that temp sensor salt water proof?

[Sinbad]

Originally Posted by mariusmeyer

How can one make that temp sensor salt water proof?

Coat it in some form of inert resin or plastic?

[Zombie]

You can do a DIY aout top up for under R200

Have you thought of putting the fans ona simple timer aswell?

[mariusmeyer]

Has anyone modified a heater? If you can reverse the switch you can make it to switch the fans on when a temp is reached.

[johnathan]

howzit
there's a good diy top up here somewhere been using it since the thread was made with no issues,i think it was pitolshrimps design.

[Pistolshrimp]

Ive actually thought about the radiator type cooler, but as regal mentioned the only thing u can use is metal and metal corrodes, u could use titanium tube but it would be freaking expensive.

[fly*]

meh...soldered the circuit together last night and it don't work. Well it works but not like its supposed to. I can see the thermistor resistance building and getting lower as it gets hotter or colder but it seems to have no effect on the relay unless the potentiometer is set all the way up ?! i'll have some of the electronic gurus at work take a look at it to see where i might have screwed up.

But I can confirm that it does work with 12V and that if it does work, it should work a treat....if it works

[franscubitt]

If you have space you can use a FW evaporative chiller, You just need fresh air.
It wont work in a closed room.
For an auto topup, use a 1.5 lit coke bottle inverted. works fine, just looks Kak.
Auto topup is the answer, best thing I ever built.
Be advised, if you are building a 393 or similar comparator cct for your temp controll they tend to drift with temp change. best to have the power supply external to the box with the sensor cct.
The ideal is a digital ic where you can set the on/ off parmeters.
If you dont come right PM me and I can send you my circuit.

[fly*]

Thanks franscubitt.

Just had one of the techies take a look at the circuit and he reckons what I've done is A OK, so either i'm going nuts or its a kak circuit I'll see if maybe changing the pot values make a diffs, currently its a 470 ohm trimmer, we are thinking of putting maybe a 330 ohm instead to see what happens. Dunno why I should be trying to fix something that should be working from the start but theres a no warranty on it so...

If I dont come right with this one i'll gladly take a look at what you have.

[fly*]

Well my idea with the thermostatically controlled relay didnt work the range between on and off is too great. That is, it'll only switch on when its seriously hot and then switch off when it seriously cold, kinda defeating the purpose really But I did have fun travelling back to my youth and building electronic kits

My next idea is just to maybe get a timer and and switch the fans on at 2 hour intervals ??? that should work, my lights aren't the problem tbh, they dont seem to do much damage at all (bear in mind this is a stock Boyu TL450 with 36w FL's) so the 2 hour interuption should be just enough to keep everything balanced.

I'll start working on an autotop idea soon

[mariusmeyer]

In stead of the 2hour interval rather try more smaller intervals. Like 30mins on, 60mins off. I'm thinking of 15min on, 30min off. I am also going to experiment with fan speeds, so instead of 15min of full blast I am going to try a constant lower voltage and see if that works as well.

[fly*]

The timer im thinking of buying only has 2 hour intervals, i'll see if I can find anything else.

[hotdog83]

The normal ones at the hardware store has increments of 15 minutes, but not sure how long they will last if they switch on and off every 15 minutes...

[mariusmeyer]

You get the cheap ones that have 15min intervals.

[fly*]

Just bought a digital one...8 on/off with 128 programs. Doesn't look like it'll do what i want though.

[mariusmeyer]

The digital ones are more rigid than the el cheapos. I prefer thecheap ones as they have those little dip switches all way round. Much easier to use.